Question

A convex lens of focal length 10 cm is placed at a distance of 12cm from a wall. How far from the lens should an object be placed so as to form its real image on the wall.

Answer 1

Answer:

Hola‼......❤✌

As we know,

Lens formula is

1/v -1/u = 1/f

Sign conversation is distance from the centre of the lens to be positive in one direction & negative to the other.

=> 1/12-1/u= 1/10

=> 1/u = -1/60

=>u = -60

The object to be place on side opposite to that of the wall at a distance of 60 cm from the lens.

Hope it’s helpful....... ☺

Answer 2

Given:-

f =10cm

v = 12cm

= 1/f = 1/v-1/u

= 1/10 - 1/12 = -1/u

= 1/60 = -1/u

u = -60cm

∴The object must be placed at a distance 60cm in front of the lens